Cylinder head of internalcombustion engines



Dec. 26, 1944. R, K. CRQWE ETAL 2,366,005

. CYLINDER-HEAD OF INTERNAL-COMBUSTION ENGINES Filed Oct. 8, 1941 2Sheets-Sheet 1 Dec. 26, 1944. R. K. c RowE ETAL 2,366,005

CYLINDER-HEAD OF INTERNAL-COMBUSTION ENGINES Fi1ed ost. a.. 1941 2sheets-sheet 2 .fm/@mfom Patented Dec. 26, 1944 HEAD OF INTERNAL-COMBUSTION ENGINES I Robert 'Kelman Crowe and Harvey Mansell, Bristol,England, assignors Bristol Aeroplane Company England, a British company`October 8, 1941,Serial No. 414,204 Great Britain March A3 Claims. ('Cl.123;-171) Application In I'his invention relates to cylinder-heads'ofinternal-combustion engines of the air-cooled sleeve-valve type. Thecylinder headof a sleevevalve engine comprises a tending into thecylinder and separated from it by a space in which the sleeve rotatesand reciprocates, and a circular base-portion extending across thecombustion space. The base-portion thus liesat the bottom of a deeprecess in the head and, in view of the difficulty of forming coolingfins on the outer surface of the base, it has already been proposed tomanufacture the two portions separately and secure them together byscrewing one part into the other after the fins have been formed on thebase.

In view of the high duty of modern internalcombustion engines, andparticularly of aero-` engines, one of the most serious problems is toprovide adequate cooling for the cylinder-head, and particularly for thebase-portionin heads of the kind described above, and it is an object ofthe present invention to provide an improved joint between the twoportions of the head so as to give improved conductivity Iof heat fromthe base to the cylindrical portion, and also to give a satisfactorilystrong joint.

According to the invention, the two portions of a cylinder-head of aninternal-combustion engine of the kinddescribed are lformed withcomplementary surfaces which interengage by an interference t. The twoportions preferably interengage by complementary cylindrical flangesfitted one within the other and, according to another feature of theinvention, the engaging surfaces are tapered in such sense as tointerlock with one another.

In the accompanying drawings:

Figure 1 is a sectional elevation on the line I-I of Figure 2 of acylinder-head in accordance with the present invention, and

Figure 2 is a plan of Figure 1, with certain parts omitted.

The cylinder-head comprises a cylindrical portion I having a radialshoulder I I which engages the end of the cylinder. The portion I0 iitsWithin the cylinder and provides an annular 'space around it toaccommodate asleeve-valve. This portion I0 is formed with cooling finsI2, I3 which may be arranged in any desired manner to give an effectivedissipation of heat.

In the particular construction shown, the iins l2 extend upwards fromthe upper surface I4 of the head and downwards in the cylindricalportion I0, and are connected to a more or less cylindrical wall or baleI which partially surcylindrical portion ex- Charles o The Limited,Bristol,

roundsl the space in the middle of the head `in which the sparking-plugsare located by holes 30. A similar construction is provided for the finsI3 which are associated with a baffle IB. With this arrangement, coolingis effected by a flow of air along the top of the cylinder-head from theright-hand side in Figure l, inside the engine-cowling I1, and thebaiiie I5 causes this stream to now downwards to the lower part of thehead, whence some passes up the central space. around the sparking-plugsto 'cool them and the remainder passes up between the baffle I6 and theadjacent wall around the ns I3. A

` suitable baffle I8 is provided between the upper margin of the ns I2,I3 and the cowling to ensure this direction of flow of the air andbaflles 3l (Figure 2) assist in this direction of the airflow.

The base-portion of the cylinder-head comprises a circular plate I9formed with an upstanding flange or rim 20, and it has formed on itcooling fins 2| which extend parallel with one another across the uppersurface of the plate I9, as shown most clearly in Figure 2. The airstream above-mentioned flows between these fins through the head.

The cylindrical portion I0 of the head terminates in a flat annular face22 which abuts the shoulder surrounding the flange 20, and the internalsurface 23 of the part I0 is of complementary shape to the externalsurface of the flange 20.

The base-portion I9, therefore, is engaged within the cylindricalportion Ill and its engagement is by an interference fit. In the case ofa cylinder-head about 6 inches in diameter, the interference is from0.001 to 0.004` inch, and the assemblage of ing-on process. This can beeffected by heating the portion l0 to, say 250 C., or the necessarytemperature-diierence can be obtained by cooling the base-portion I9 andheating the cylindrical portion 20.

In order to increase the strength of the joint between the two parts,the internal surface 23 of the part IIl may diverge upwardly in aconical form, the angle of the taper being, for example, 1 so that whenassembled the parts are interlocked by a kind of dove-tailed jointwhereby separation of the two parts is positively prevented.

It is customary to provide sealing-rings in the cylinder-head `to engagethe inner surface of the sleeve-valve, and it is an important feature ofthis invention that the groove or grooves 24 the parts is effected by ashrinkparts, and the total result is that tliexheatin the contactobtained at the l Y. surface 23 by the interference Iit between the'hottest portion of the head, namely, thebase L9,

is adequately conducted away to the cooling ns 2| and to the cylindrical.body-portion. I0 and j thence to the cooling fins l2, :i3 fromcwhich.it is dissipated in the stream of cooling air. We claim:

1. rIn an air-cooled internalcombustion en gine, a recessed cylinderhead comprising a cir-4` cular base formed integrally with closelylspaced coolingwns extending parallel to one another and .an upstandingperipheral an'ge, a cylindrical bodyportion interengaged tightly 4'withthe iiange land formed with radiallyI disposed in- 2. In an air-cooledinternal-combustion engine, a recessed cylinder head comprisingl aV cir:

l-indrica'l body-portion cular base formed integrally with closelyspaced ooling ns extending parallel to one another from side to side ofthe base and also formed 3. In an air-cooled internal-combustionengine,.a recessed kcylinder head comprising a cyformed with two sets ofradially disposed cooling ns integral with its inner surface, united-attheir inner ends by a baffle across-its top` surface; the ange'on `whichbase is engagedY in the body Withan interference't insuch thatV the twosets of ends of the: i'lns on the base and the ns onf'the baseextendinto the body.

l ROBERT KELMAN-CROWE;

HARVEY CHARLES MANSJEJLL.

